feat(merge-tree): add obliterate partial length tests

[connorskees]

Description

Test partial length outcomes when executing the obliterate op.

ado 1761

[msfluid-bot]

⯅ @fluid-example/bundle-size-tests: +120 Bytes

Metric Name	Baseline Size	Compare Size	Size Diff
aqueduct.js	397.3 KB	397.34 KB	⯅ +40 Bytes
connectionState.js	680 Bytes	680 Bytes	■ No change
containerRuntime.js	196.25 KB	196.25 KB	■ No change
loader.js	153.76 KB	153.76 KB	■ No change
map.js	42.84 KB	42.84 KB	■ No change
matrix.js	131.78 KB	131.82 KB	⯅ +40 Bytes
odspDriver.js	151.87 KB	151.87 KB	■ No change
odspPrefetchSnapshot.js	39.77 KB	39.77 KB	■ No change
sharedString.js	152.99 KB	153.03 KB	⯅ +40 Bytes
Total Size	1.27 MB	1.27 MB	⯅ +120 Bytes

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Baseline commit: 44bb24d6b441ae5bd52c71a481e4c1cb75df5ff3

Generated by :no_entry_sign: dangerJS against a8471158993da4703c001aa2f672359dbcc9ff02

[github-actions[bot]]

This commit is queued for merging with the next branch! Please ignore this PR for now. Contact @microsoft/fluid-cr-infra for help.